1. Field of the Invention
The present invention relates generally to a hearing test technology and, more particularly, to a hearing test method and apparatus for improving a measurement accuracy and a test speed in finding the auditory threshold used to discriminate a sound.
2. Description of the Related Art
The number of persons who have difficulty in hearing is increasing every year. Especially, noise-induced hearing loss is rising rapidly. In addition, age-related or any other cause-induced hearing loss keeps on growing. Being exposed to everyday noises, such as listening to very loud music over many years, may have contributed to many hearing loss.
FIGS. 1 to 5 illustrate two conventional hearing test methods. One of them is based on a descending approach, and the other is based on an ascending approach.
As shown in FIG. 1, the descending approach is to measure a person's sense of hearing by gradually decreasing a test sound from a higher level (intensity) at different frequencies such as 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz and 8 kHz. In contrast, as shown in FIG. 2, the ascending approach gradually increases a test sound from a lower level at various frequencies. Normally the descending approach yields a lower result of the auditory threshold by 5-10 dB than the ascending approach. According to such conventional hearing test methods, process of selecting a frequency, outputting a test sound for a selected frequency and checking a response or not are sequentially performed.
In another conventional hearing test method, a method based on a mixed approach is known in the art. Referring to FIG. 3, the mixed approach is to find an initial auditory threshold through the ascending approach and then determine the final auditory threshold through the descending approach, or vice versa. Referring to FIG. 4, a related application ‘uHear’ registered in the application store operated by Apple Inc. is an example of using the mixed approach of ascent after descent.
In order to improve a test speed of the descending or ascending approach, still another conventional hearing test method is disclosed in the Korean Patent Publication No. 2010-22880 (US Publication 20100137739). Briefly, as shown in FIG. 5, this method is based on a grouping approach that uses two or more test sound sets. The grouping approach is to output some sets of test sounds and receive a user's response regarding how many test sounds could be heard.
Among the above-discussed conventional methods, the descending approach and the ascending approach are designed offer all sound pressure levels up to the auditory threshold for each frequency to a user. Therefore, a test duration is much longer, and also there is a difference in the auditory threshold between the descending and ascending approaches.
In case of the mixed approach, the required test duration nearly double when compared with the descending or ascending approach which in turn lowers a user's attention span. Further, ascent or descent by a uniform difference in sound pressure during test may allow a user to predict the next test sound and thus create an illusion as if he or she had heard a sound.
In case of the grouping approach, a test duration is relatively shorted compared to other approaches. However, since all test sounds have to be heard, it has the same drawbacks of lowering a user's attention span. Also, since the test duration is varied according to a region of the auditory threshold, there is a possibility that a difference in test accuracy will be caused due to variation in test concentration.
Accordingly, there is a need to improve the way to assess one's hearing.